Green unroasted coffee beans remain useful for extensive time periods. When roasted, unground coffee beans begin to lose flavor in a day and shall have lost almost all flavor in a week. Ground coffee deteriorates even faster.
As the people become more sophisticated about food and coffee, the consumer market demand grows for better quality coffee beverages. Specialized coffee shops have arisen to meet this demand. However, many of these shops provide no in-store roasting. Roasted beans are shipped from a central location to shops all over the country. The coffee served at these shops has spent the prime of its life in transit. The pre-roasted whole-bean coffee one buys in supermarkets is even older.
Freshly roasted and ground coffee is vastly superior compared with these pre-roasted products. Various systems are known that attempt to roast green coffee beans and otherwise process them shortly before grinding and using them to make fresh coffee. See for example, U.S. Pat. Nos. 3,964,175, 4,326,114, and 6,123,971. These disclosures recognize the value of rapid cool down of roasted beans but suffer from various process steps that prevent production of a good quality product. For example, these systems fail to enable the operator to visually inspect the roasting bean color to control various process steps that can produce a better quality final roasted bean.
Various characteristics of the roasting beans can be used to indicate or measure quality during the roasting and cooling cycle, such as the color of the roasting beans, smell of the rising aroma, crackling sounds of the beans, and the length of time, roasting energy consumed, and bean temperature. Technical problems must be solved to effectively use one or more of these characteristics. For example, the generally known fluidized bed coffee bean roaster uses streams of radiantly heated hot air to carry, circulate, and roast the beans. However, the operator of these systems cannot observe the individual bean color but only a swirling mass during the roasting. Operation of other household units of the drum type cannot visually inspect the beans while roasting. All of these units do not attempt to minimize the smoke produced such that they need to be vented or used outside to avoid creating a polluted environment. Similarly many or these units fail to collect chaff and spread chaff over an already polluted environment. Most of the household fluidized bed units roast only 2 to 3 oz. (¼ to ½ cup) of green beans and have little tolerance for different amounts. These limitations are due to design but are mainly due to the principles of operation and power use of the fluidized bed devices.